Arm rests serve a variety of functions. An arm rest primarily provides support to a person's arm in an elevated position in a variety of environments. In many cases, this occurs while a person is sitting down, but is not limited to this circumstance.
Beyond merely supporting an arm, arm rests serve other functions such as holding one or more beverages. These beverage holders are generally cylindrical and are of a sufficient depth and width to accommodate most beverage container shapes. However, one of the primary problems with portable arm rests having beverage holders is maintaining the beverage in an upright position to avoid spillage when the portable arm rest is in use. The weight of a beverage container with its contents in a holder must be balanced against the weight of the supporting arm rest to ensure that the arm rest maintains the beverage in a stable and upright position. Otherwise, a beverage with its contents will make the arm rest top heavy and likely to turn over. In some cases, a single beverage holder may be positioned along the centerline of the upper surface of an arm rest in order to balance the weight of a container when held in the beverage holder with respect to body of the arm rest. In other cases, a beverage holder may be placed across the centerline of the arm rest so that the arm rest remains balanced. Neither of these functions alone are sufficient to prevent the arm rest from becoming unstable.
This problem becomes more difficult when the arm rest is used on an uneven and/or unstable surface that tends to cause the arm rest to tip over more readily when holding one or more beverages in response to the weight imbalance. In some cases, an arm rest is secured by a supporting structure or mechanism that holds the structure in a fixed position. However, this prevents the arm rest from being readily moved from one environment to another without undue effort. Most arm rests that are designed to be portable use have a planar shaped bottom surface that does not conform to uneven supporting surfaces such as a furniture cushion for a couch or car seat. This makes them further unstable and, as such, incapable of holding a beverage without the risk of turning over.